1. Field of the Invention
The present invention relates to a resin molded product to which a metal heating element such as a fuse is attached.
2. Description of the Related Art
<Resin Molded Product Disclosed in PTL 1>
A fuse is ordinarily attached to a resin molded product (see PTL 1). FIG. 5 is an exploded perspective view of a resin molded product described in the patent literature 1 and shows a fuse holder and a fuse. In FIG. 5, to a first attaching part 120S and a second attaching part 130S provided in a holder main body 110S of the fuse holder 100S as the resin molded product, both ends of the fuse 200S as a metal heating element are attached and fixed by using bolts 300S.    PTL 1: JP-A-2005-276494<Problems of Resin Molded Product Described in PTL 1>
There is a large difference in a coefficient of linear expansion between the fuse holder 100S formed with a synthetic resin and the fuse 200S formed with metal. Ordinarily, the coefficient of linear expansion of the fuse holder 100S is larger by 10 to 19 or so than that of the fuse 200S. Accordingly, a problem arises that an elongation of the fuse holder 100S is larger than an elongation of the fuse 200S at high temperature, and even under no state of over-current, the fuse 200S is forcibly pulled by the fuse holder 100S so that the fuse is cut.
<Resin Molded Product of Advanced Invention>
Thus, the applicant of the present invention develops, as means for solving the problems of the invention disclosed in the PTL 1, a resin molded product which can prevent a fuse from being cut due to the difference in a coefficient of linear expansion as an advanced invention. FIG. 6 shows the resin molded product according to the advanced invention. FIG. 6(A)(1) is a front perspective view and FIG. 6(A)(2) is a back perspective view. FIG. 6(B)(1) is a front view and FIG. 6(B)(2) is a back surface view. In FIG. 6, the resin molded product 100 of the advanced invention is formed with a synthetic resin including glass fibers. As shown in FIG. 6(A)(1), on a front side of the resin molded product 100, a first attaching part 120 and a second attaching part 130 for attaching a fuse are provided so as to stand upright on a main body 110. Two gate positions 400 and 410 which form the resin molded product 100 are provided in a back side of the resin molded product 100 so as to be located substantially at an intermediate part of a straight line that connects the first attaching part 120 to the second attaching part 130 and linearly symmetrically come close to each other (see FIG. 6(A)(2)). Further, since the resin molded product 100 includes the glass fibers, the orientation of the glass fibers GF that appears along a flowing direction of the resin is formed in directions shown by FIGS. 6(B)(1) and 6(B)(2). When the resin having the glass fibers is used, a thermal resistance is high and a plastic deformation of the resin molded product 100 due to the heat of the fuse can be prevented. Further, since most of the orientation of the glass fibers is directed to a direction that connects the first attaching part 120 to the second attaching part 130 for attaching the fuse, a coefficient of linear expansion of the resin molded product is close to a coefficient of linear expansion of the fuse. Thus, the number of times that the fuse is cut is reduced.